The present invention concerns a device for dispensing a product held in a container, and more specifically a precompression pump.
The present pumps generally comprise a pump body having a pump chamber, an inlet valve, an outlet valve, a piston sliding in said pump body and an actuating shaft in order to activate the pump by means of a pusher. A return spring acting on the actuating shaft and/or on the pusher, returns the pump to its rest position after each actuation.
The present precompression pumps generally comprise in addition a differential piston forming an outlet valve and sliding in the pump body or on the actuating shaft, under the effect of a precompression spring.
Such a known precompression pump is revealed in document FR-2 346 056.
These known precompression pumps, even though they operate correctly, present a certain number of drawbacks. In fact, they contain numerous parts and are therefore difficult to manufacture and complicated to assemble. Furthermore, their dimensions, in particular their height, are quite considerable, which can represent a disadvantage from the point of view of adaptability on small containers, from the point of view of stocking or from an esthetic viewpoint. Besides, they do not comprise simple means and which do not involve increased manufacturing cost, which permit adjustment of the volume of the product dose discharged each time the pump is actuated.